The present invention relates generally to powder dusters.
It has been generally known for many years, as exemplified by U.S. Pat. No. 535,439, dated Mar. 12, 1895 and U.S. Pat. No. 1,609,674, dated Dec. 7, 1926, to provide insect dusters and sprayers of the type in which wall portions of a bellows or container could be manually deformed to compress air within the container to force a powder therein through an opening or openings of a discharge tube and emitted from an exterior end of the tube or a connected nozzle into the atmosphere for dusting purposes. Such structures were at most quite crude, and operatively leave much to be desired. For example, these prior devices were not adapted to operate effectively in all positions of orientation, and more particularly did not operate effectively when the container was only partially filled with the powder.
Later patents, as exemplifid by U.S. Pat. No. 2,981,444, dated Apr. 25, 1961 and U.S. Pat. No. 4,091,966, dated May 30, 1978, disclose squeeze-type dispensers which attempt to overcome many of the problems associated with the earlier devices, and disclose embodiments which allegedly operate in either an upright or inverted tilted position. In practice, however, it has been found that there are positions in which these known devices did not operate satisfactorily, and particularly, when the containers were only partially filled with powder.
Both of the above noted patents, recognize the existing problem in which compaction of the powder in the areas of the openings in the discharge tube produced a deleterious effect which seriously limited the operative effectiveness of the device. Thus, in attempting to solve this and other problems inherent in the known devices, the patentees have also provided supplemental intake nozzle passages for communicating with the air in the top end of the container, when operating in a substantially upright position.
More specifically, the first of the above noted patents utilizes an elongated discharge tube provided with a plurality of longitudinally spaced openings therein, the tube being connected to a nozzle within which it communicates with a nozzle mixing chamber that is also in communication through one or more supplemental passages with the adjacent upper end interior of the container.
The second of the above noted patents (Pat. No. 4,091,966) also utilizes a supplemental passage for connecting the nozzle passage with the upper end interior of the container. The discharge tube is in this case formed by interconnected parallel tubes having their lower ends connected by a fitting which provides a relatively sharp U-bend with a single orifice at the bottom of the U-bend portion. The upper end of one of the parallel tubes is connected with a nozzle, while the other parallel tube has its upper end positioned in communication through an unrestricted end opening with the upper end interior of the container.
Applicants have discovered through exhaustive tests on squeeze-type powder dispensers, constructed after the manner disclosed in the above U.S. Pat. Nos. 2,981,444 and 4,091,966, that the successful operation of squeeze-type powder dispenser particularly when in tilted or inverted positions or only partially filled with powder, is affected by a number of important factors which briefly include, for example:
The present invention is more specifically directed to a squeeze-type dispenser which is designed and constructed to take maximum advantage of the foregoing factors and considerations in overcoming the existing problems an disadvantages which are inherent in the presently known and available devices for dispensing of powder in a cloud formation.